This project will continue studies with a unique staphylocidal lipid first detected in staphylococcal abscesses. Attempts will be made to determine the cell type producing the precursor for the cidal lipid and the mechanism whereby the cidal lipid is generated. Studies will be conducted to determine whether differences in extracellular accumulations (capsules, or slime), cell wall, or the membrane account for normal differences in strain sensitivity to the lipids, and whether alteration in these structures can lead to resistance. The production of cidal lipid during the course of lesion evaluation in various host species will be measured using a biologic assay previously developed. The nature and distribution of an inhibitor for the cidal lipid will also be explored. Other studies will attempt to purify and characterize a newly detected epidermal toxin which may be involved in a recently described toxic shock syndrome. The incidence and distribution of toxigenic strains and the possible existence of multiple antigenic types of toxin will be investigated. Studies will evaluate the binding or degradation of S. aureus exfoliatin in vivo and efforts made to improve toxin immunogenicity by coupling to carriers. Alternate sites of toxin action and the effects of steroids on host sensitivity will also be examined. The ability of specific carotenoids to alter S. aureus delta toxin activity will be studied. Attempts will be made to prepare an antibody to delta toxin and to use this antibody to measure toxin production in vivo.